Methanol is one potential raw material that can be used for industrial oxygenate-to-olefin conversion reactions. Industrial scale production of olefins requires an abundant source of methanol or another oxygenate to provide the feedstock. U.S. Pat. Nos. 6,444,712 B1 and 6,486,219 B1 to Janda, disclose a method for producing olefins from methanol by way of using natural gas to make the methanol. The method includes converting the methane component of the natural gas to synthesis gas (syngas) using a steam reformer and a partial oxidation reformer. The syngas from each reformer is combined and sent to a methanol synthesis reactor. The combined syngas stream to the methanol synthesis reactor desirably has a syngas number of from about 1.4 to 2.6. The methanol product is then used as a feed in a methanol to olefin production process.
Gas reserves typically include other compounds, such as CO2, that are separated from the natural gas prior to use. In some conventional processes, this CO2 is considered a waste product that is vented to the atmosphere or otherwise disposed of. Other processes have attempted to use CO2 as a source of carbon for other reactions. U.S. Pat. No. 6,248,794 describes a process where CO2 separated from a natural gas stream is added with the natural gas stream into a reformer for producing synthesis gas. The synthesis gas is then fed into a reactor for conducting a Fischer-Tropsch reaction to create heavy hydrocarbons. Published application WO98/36038 describes a method for converting natural gas into methanol in a conversion plant where CO2 recovered from the natural gas is recycled to the inlet stream of the conversion plant.
What is needed is a method for increasing or optimizing the efficiency of methanol production for use as feedstock for a methanol-to-olefin conversion process. The method should allow for improvement in the amount of methanol produced while minimizing the amount of cost required for additional equipment or raw materials. What is also needed is a method for reducing or eliminating the need to dispose of CO2 found in gas reserves. The method should be environmentally friendly, leading to minimal or no release of greenhouse gases into the atmosphere. The method should also allow the CO2 to be processed while adding a minimum of additional equipment.